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[Frama-c-discuss] Assigns clause

Thank you for your reply.

We have tried to run the specification suggested, but it did not work, the
GWhy GUI did not open. It showed the following message
[kernel] user error: syntax error while parsing annotation

After some attempts we figured out that the problem seems to be the
requires clauses, because without them it runs.

We have searched some examples in the Jessie Tutorial (
http://krakatoa.lri.fr/jessie.html) with requires clauses inside behaviors,
but we have not found. We found an example in the reference manual of ACSL
Version 1.4 and we tried to run it, but it did not work too.

We are using the Jessie plugin. Why requires clause inside behavior is not
working? Is it possible to include requires clauses inside behavior in the
Jessie plugin?

Best regards,
Nanci, Rovedy, Luciana

*/

// ######################################################
// Example of the reference manual of ACSL Version 1.4
/*@
  behavior p_changed:
  assumes n > 0;
  requires \valid (p);
  assigns *p;
  ensures *p == n;
  behavior q_changed:
  assumes n <= 0;
  requires \valid (q);
  assigns *q;
  ensures *q == n;
@ */

void f (int n, int *p, int *q)
{
  if (n > 0)
    *p = n;
  else
    *q = n;
}


2013/9/25 Pariente Dillon <Dillon.Pariente at dassault-aviation.com>

>  Hi,****
>
> ** **
>
> You may give a look to the ACSL reference manual, to the notions of
> behaviors/assumes.****
>
> The following is an example of what the Interp_Tab_1s spec could look like.
> ****
>
> ** **
>
> /*@ ****
>
> ** **
>
> requires \valid (Ptr+(0 .. 1));****
>
> requires Itab == 0 || Itab == 1;****
>
> ** **
>
> behavior Itab_false:****
>
>   assumes Itab != 1;****
>
>   requires \forall integer j; 0 <= j < 3 ==> \valid (Ptr[0]+ j);****
>
>   requires \valid (Interp+(0 .. 2));****
>
>   assigns Interp[0..2];****
>
>   ensures  \forall integer j; 0 <= j < 3 ==> ****
>
>                 \abs ((Interp[j]) - (*(Ptr[0]+ j))) < BOUND;****
>
> ** **
>
> behavior Itab_true:****
>
>  assumes Itab == 1;****
>
>   requires \forall integer j; 0 <= j < 2 ==> \valid (Ptr[1]+ j);****
>
>   requires \valid (Interp+(0 .. 1));****
>
>   assigns Interp[0..1];****
>
>   ensures  \forall integer j; 0 <= j < 2 ==>****
>
>     \abs ((Interp[j]) - (*(Ptr[1]+ j))) < BOUND;****
>
> ** **
>
> complete behaviors Itab_false,Itab_true;****
>
> disjoint behaviors Itab_false,Itab_true;****
>
> ** **
>
> */****
>
> ** **
>
> ** **
>
> HTH,
> D.****
>
> ** **
>
> *De :* frama-c-discuss-bounces at lists.gforge.inria.fr [mailto:
> frama-c-discuss-bounces at lists.gforge.inria.fr] *De la part de* Rovedy
> Aparecida Busquim e Silva
> *Envoy? :* mardi 24 septembre 2013 21:54
> *? :* Frama-C public discussion
> *Cc :* Nanci; Luciana Akemi
> *Objet :* [Frama-c-discuss] Assigns clause****
>
> ** **
>
> Hi,
>
> We have a doubt related to assigns clause.
>
> All VCs of the attached function were proved.
>
> We wrote an assigns clause to the Interp array taking in account three
> elements:
>  assigns Interp[0..2];
>
> However, we would like to write a more precise assigns clause for the
> Interp array that has two or three elements according to Itab value.
>
> In the requires and ensures clauses the Itab value was considered, for
> example:
> requires Itab != 1 ==> \valid_range (Interp,0,2);
>
> requires Itab == 1 ==> \valid_range (Interp,0,1);
>
> How to write the assigns clause for the Interp array taking in account the
> Itab value?
>
> Best regards,
> Nanci, Rovedy e Luciana****
>
> _______________________________________________
> Frama-c-discuss mailing list
> Frama-c-discuss at lists.gforge.inria.fr
> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/frama-c-discuss
>
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